1. Field of the Invention
The present invention relates to a Plasma Display Panel (PDP) displaying images using a gas discharge phenomenon.
2. Description of the Related Art
Plasma Display Panels (PDPs) are flat panel displays that are considered to be next generation flat panel displays due to their wide screens, and excellent display characteristics such as high image quality, ultra-thin thickness, and light weight. In addition, it is easy to fabricate a PDP and to enlarge the panel.
PDPs can be classified into Direct Current (DC) PDPs, Alternating Current (AC) PDPs, and hybrid PDPs according to their driving method. In addition, PDPs can be classified into opposing discharge PDPs and surface discharge PDPs according to their discharge structure. Most PDPs produced recently have been three-electrode surface discharge PDPs.
A three-electrode surface discharge PDP includes an upper substrate and a lower substrate facing the upper substrate. Sustain electrode pairs are disposed on a lower surface of the upper substrate, and an upper dielectric layer embedding the sustain electrode pairs and a protective layer covering the upper dielectric layer are formed sequentially thereon. Each of the sustain electrode pairs includes a scan electrode and a common electrode. In addition, the scan electrode and the common electrode respectively include transparent electrodes and bus electrodes.
Address electrodes extending perpendicularly to the sustain electrode pairs and a lower dielectric layer embedding the address electrodes are formed on an upper surface of the lower substrate. Barrier ribs are formed on the lower dielectric layer to define a plurality of discharge cells. The barrier ribs extend in two directions crossing each other in a matrix pattern. A phosphor layer is formed on the barrier ribs and on the lower dielectric layer, and a discharge gas is contained within the discharge cells.
In the PDP having the above structure, a plasma is formed by a discharge caused by the sustain electrode pairs, and the phosphor layer is excited by vacuum ultraviolet rays emitted from the plasma. Then, visible light is emitted by the phosphor layer to display image.
However, in such a three-electrode surface discharge PDP, about 40% of the emitted visible light is absorbed by the sustain electrode pairs, the upper dielectric layer, and the protective layer formed under the upper substrate while the remaining visible light pass through those layers. Therefore, the light emission efficiency is low. In addition, if the same image is displayed for a long time, charged particles of the discharge gas may collide with the phosphor layer, thus causing a permanent residual image.
When forming the PDP, the upper portion of the PDP including the upper substrate and the lower portion of the PDP including the lower substrate are sealed, and an air exhausting process for discharging impure gas in the PDP and a filling process for filling a discharge gas in the discharge cells are performed. In the air exhausting process, a vacuum pump exhausts the gas from the PDP through an air exhaustion hole disposed in the lower substrate while the PDP is heated. If the exhaustion of the PDP is not performed sufficiently, the discharge gas to be filled in the panel later and the impure gas remaining in the panel mix, and the composition of the discharge gas is changed, and accordingly, a display operation becomes unstable. Since the discharge cells are sealed by the barrier ribs, sufficient air ventilation is interrupted, and thus, it takes a long time to exhaust the impure gas and fill the discharge gas. In addition, the impurities remain in the discharge cells that are located far from the ventilation hole. Especially in PDPs with super-fine and high resolutions, the inner structure of the panel is fine, and thus, difficulties with the exhaustion of the impure gas must be solved.